cv <name> ( <triple>, <scalar> ) ;
This defines a cv. A cv may be specified as a literal or as a variable. If specified as a variable, it must have a name. All of its components are identified by position rather than by keywords. They are interpreted as
( (x, y, z), w )
x, y, and z, are the coordinates of the cv; w is its weight.
cv u0 ((-1, 0, 0), 1); cv u1 (( 0, 0, 0), 1); cv u3 (( 1, 0, 0), 1); cv u3 (( 2, 0, 0), 1);